I'm obliged to pass along this anecdote that was told to me by a friend.
One evening my friend's husband was having some pains. They persisted, so he went to the hospital, where he died the next day. After a brief examination, the doctor asked my friend if he worked on a computer. She was rather surprised that he knew, and the doctor clarified.
It has become rather common that people die of blood clots, due to long periods spent sitting in front of computers. Its very important to get up once every two hours and move around, as this is a simple remedy that may be preventative. She has made me promise to do so, and has asked that I tell everyone I know who is in a similar situation.
I usually don't play for more than 4 or 5 hours at a time, but since I am unemployed, unmarried and do not socialize, I do so with great frequency. I can't say I actually keep track, as I find it rather humiliating to be in this situation. Sorry to be so dour, but it is rather serious; especially for the younger people on the forum. Bad habits become harder to break as time goes by.